Cultivation and afforestation techniques of Picea koraiensis

Picea koraiensis is shade-tolerant, drought-resistant, cold-resistant and fast-growing. It is not only the main tree species in the forest from Changbai Mountain to Xiaoxinganling in Northeast China, but also a common garden seedling. The cultivation and afforestation techniques of Picea koraiensis are introduced below.

Improved variety breeding

First, choose a good stubble. Pinus sylvestris var. mongolica and larch stubble are suitable for red-bark spruce sowing land. for the bed stubble of these two kinds of trees, if the working area is small and the stubble can not be adjusted, a large amount of organic fertilizer and base fertilizer should be applied and disinfected carefully.

Second, seed sprouting. Snow storage is the best treatment, so that seedlings emerge quickly, unearthed well, and have strong resistance to all kinds of disasters.

Third, sow seeds at the right time. The sowing time is generally completed on May 5-15 of that year, and the sowing time can be stable at 8-10 ℃ according to the soil temperature at the depth of 5 cm. Three conditions need to be met: first, the soil has a good fertile structure; second, the covering material after sowing is preferably peat soil or rotten horse manure; third, timely irrigation, otherwise shading should be considered.

Fourth, choose one-year-old seedlings to change beds and big seedlings to go up the mountain. The advantage of changing the bed of one-year-old seedlings is that it can ensure the quality of changing the bed, improve the survival rate, uniform nutrition space and suitable density. If one-year-old seedlings are used to change the bed, the seedlings can be changed in the same year, and all the seedlings can be changed in the second year. With the same number of seeds, more than twice as many seedlings can be obtained, and the economic benefit is obvious.

Prevent frost and cold

The expansion of leaf buds and the extension of new growth nodes of this tree species are relatively late and are generally free from frost damage. However, the late frost occurred in late May or early June suffered seriously. If the temperature reached-2 ℃ in this period, the seedling mortality rate was 24%, when it reached-4 ℃, the mortality rate was 34%. Although measures to prevent low temperature could be taken when it reached-5 ℃, the seedling mortality rate was more than 70%. Comprehensive prevention and control measures should be taken for frost. Such as smoke, grass cover, plastic film, irrigation and so on.

Site condition selection

According to the biological characteristics of Picea koraiensis, the best site conditions are sunny slope and semi-sunny slope, the slope is 8-12 degrees, the soil layer is deep, the black soil layer is more than 20 cm, and the dark brown soil is well drained, especially on the clear cutting site. Under such site conditions, the 20-year-old tree height of the plantation can reach more than 8 meters, and the poor condition is only about 6 meters. The growth and preservation of different site conditions are also different.

Land preparation

Land preparation should be carried out in the autumn of the previous year. It is best to be in August-September, during this period, there are more Rain Water and high temperature, which is conducive to the spring planting of seedlings in the following year. Open holes are adopted in soil preparation to create conditions for afforestation with top oars. The specification of soil preparation is 60 × 60 × 25 cm. First, root out the turf, break the clods, pick out sundries, and pile the soil in the cave on the north side of the hole. In the areas with strong grass roots and poor drainage, the method of building a high platform with a height of 30-40 cm and a specification of 1 m × 2 m was carried out, and the afforestation group was used. For clear-cutting land, the slope is less than 25 degrees, and banded land preparation can be carried out.

Afforestation

Afforestation in spring is an important measure for successful reforestation of Picea koraiensis, which requires that it should not exceed 2 days at most from seedling to planting. For uphill seedlings, high-quality seedlings with a height of more than 25 cm, ground diameter of more than 0.5 cm, main root length of about 15 cm, lateral roots of more than 12, strong growth, good development, full terminal buds and no diseases and insect pests should be strictly quarantined before going up the mountain.

When planting, the seedlings should be planted in the center of the hole, straight, straightened, root system stretched, layered soil cultivation, light lifting and steadiness, and 3 plants were suitable for afforestation in the plant group. The initial planting density of afforestation, such as excessive density, not only increases the cost of soil preparation and seedlings, but also takes a lot of work to nurture through light, which is not cost-effective in the first thinning. From years of practice, it is reasonable to plant about 4400 seedlings per hectare.

Tending and management of young forest

According to the characteristics of Picea koraiensis, young trees need a certain amount of light, and they should be nurtured for 5 years, that is, 2, 3, 2, 2, 1. In particular, the first tending after afforestation is particularly important, focusing on soil cultivation, straightening, steadiness, and never shoveling cave surface soil and injured seedlings.

1. In the first year, the hole is enlarged by 50 cm, the soil is over 1-2 cm above the stem of the seedling, and the seedlings with an angle of more than 20 degrees should be upright.

two。 The second year is mainly weeding and soil cultivation.

3. Weeding, cutting and irrigation in the third year.

4. In the fourth year, remove plants or shrubs that hinder the growth of young trees.

5. In the fifth year, the banded operation comprehensively weeded, cut and cut off competitive plants, retaining the three hardened areas. Long-acting organic compound fertilizer can also be applied under certain conditions.

Transparent tending

Under the normal condition of light and moisture, the annual growth of tree height is usually more than 30 cm. The deficiency of this standard is due to the lack of light, showing spruce crown spreading, dark green color and weak trunk, so light transmission measures must be taken in time. The light transmission is completed in 5-15 years. Cutting the upper layer, liberating the lower layer, and artificial pruning can also be carried out.

Growth and tending

The growth and tending of the general plantation starts from the Ⅱ age class, and the growth and tending of Picea koraiensis will be completed within 15-20 years. The main purpose is to adjust the stand management density, to create the most suitable nutrition space for preserving trees, and to promote the fast growth and good stem shape of trees, so as to achieve high quality and high yield. Quantitative thinning technique should be adopted in thinning of spruce plantation, and the density can be determined according to site conditions and management level.

Pest control

Several common diseases and control methods.

1. Spruce cone rust. Control method: spray 0.1% 2jue 4murD within 200 meters near the orchard to kill Rosaceae plants and thick plums. Cut off the seriously diseased wood. Strict selection of disease-free wood when picking cones. Build coniferous and broad-leaved mixed forest.

2. Spruce red spot. Control method: the spruce seedlings on the Pinus sylvestris var. mongolica forest and the nursery around the nursery were sprayed with 75% chlorothalonil from the end of May to the beginning of July for 3 years.

3. Ash felt wilt of spruce. Excessive stand density is the main inducing factor of the disease. Prevention and control methods: forest management measures such as forest cleaning, pruning and transparent cutting are taken for the plantation, and the effect is better.

The afforestation of Picea koraiensis is a long process, we can not be impatient, we have to care carefully and patiently in order to cultivate high-quality seedlings.